class Person:
    # None 是一个内置常量
    age = None
    name = None


p1 = Person()
p1.name = '张三'
p1.age = 18
p2 = p1
print(p2.age)
print(f"p1.name地址 {id(p1.name)} p2.name地址 {id(p2.name)}")
